Epoxy resin composition for a fiber-reinforced composite material, yarn prepreg, and process and apparatus for preparing the same

Abstract

To provide an epoxy resin composition suitable as a matrix resin for fiber reinforcement, and a yarn prepreg suitable in unwindability, excellent in higher processability due to drapability, high in the tensile strength of the epoxy resin composition after curing, and high in efficiency of the strength of reinforcing fibers.A yarn prepreg, satisfying the following formulae (1) to (3):where Wf is the content by weight of the fiber bundle (%), F is the number of filaments in the fiber bundle and d is the width of the prepreg (mm).An epoxy resin composition for a fiber reinforced composite material, comprising at least the following components [A], [B] and [C]:[A]: An epoxy resin mixture containing two or more epoxy resins, in such a manner that 100 weight parts of the epoxy resin mixture contains 40 to 79 parts of a monofunctional or bifunctional epoxy resin and 21 to 60 parts of a trifunctional or higher functional epoxy resin and that the epoxy resin mixture is 210 to 370 in epoxy equivalent weight[B]: Fine particles containing a rubber ingredient and insoluble in the epoxy resins[C]: A curing agent

What is claimed is:  
     
       1. A method for producing yarn prepregs, comprising the step of continuously applying a molten resin to bottoms of the grooves of a rotating grooved roller, while bringing fiber bundles into contact with the bottoms of the grooves at a position downstream in the rotating direction, so that the fiber bundles may be impregnated with the applied resin. 
     
     
       2. A method for producing yarn prepregs according to  claim 1 , wherein a blade with almost the same width as the groove width is inserted inside the groove of the rotating grooved roller, to adjust the clearance formed between the blade and the bottom of the groove, so that the amount of the molten resin to be impregnated into the fiber bundle is controlled. 
     
     
       3. A method for producing yarn prepregs according to  claim 1 , wherein the rotating grooved roller is heated. 
     
     
       4. A method for producing yarn prepregs according to  claim 1 , wherein the viscosity of the molten resin is 1 poise to 200 poises. 
     
     
       5. A method for producing yarn prepregs according to  claim 1 , wherein the fiber bundles are heated to at least not lower than the temperature of the molten resin, before they are brought into contact with the molten resin. 
     
     
       6. A method for producing yarn prepregs according to  claim 1 , wherein the fiber bundles are widened before the fiber bundles are brought into contact with the molten resin. 
     
     
       7. A method for producing yarn prepregs according to  claim 1 , wherein the fiber bundles are heated and widened before the fiber bundles are brought into contact with the molten resin. 
     
     
       8. A method for producing yarn prepregs according to  claim 1 , wherein the fiber bundles are impregnated with the resin, and subsequently brought into contact with at least one rotating heating roll. 
     
     
       9. A method for producing yarn prepregs according to  claim 1 , wherein when the fiber bundles impregnated with the molten resin are wound around cores, and the temperature of the resin impregnated fiber bundles is controlled in a range of 0° C. to 35° C. immediately before they are wound around the cores. 
     
     
       10. A method for producing yarn prepregs according to  claim 1 , wherein the number F of filaments, width D (mm) and thickness T (mm) of each fiber bundle satisfy the following formulae (4) and (5): 
       
         
             F /3,000 ≦D≦F /1,200  (4)  
         
       
       
         
           20,000 ≦F ≦100,000  (5).  
         
       
     
     
       11. A method for producing yarn prepregs according to  claim 1 , wherein the resin is supplied in a predetermined amount to a plurality of grooves of the grooved roller by a piping installed in tournament style from the molten resin metering and supplying device for supplying the molten resin to the grooves of the grooved roller for impregnating the fiber bundles with the molten resin. 
     
     
       12. A method for producing yarn prepregs according to  claim 11 , wherein the molten resin metering and supplying device is a gear pump type discharger, plunger type discharger, extruder or microtube pump. 
     
     
       13. A method for producing yarn prepregs according to  claim 10 , wherein the molten resin is an epoxy resin. 
     
     
       14. A method for producing yarn prepregs according to  claim 10 , wherein the fiber bundles are carbon fibers. 
     
     
       15. A method for producing yarn prepregs according to  claim 13 , wherein the fiber bundles are carbon fibers.